It is very simple to delete a photo you added in your pics tab. You need to open up your app and go to the job or estimate in which you want to delete a photo. Follow these instructions to delete a photo from iOS and Android.
iOS
Select the picture which you want to delete and simply slide it to the left.
Once you slide it left, a red box will appear on the right side saying delete.
Just click that and that picture will be deleted.
Android
Select the picture which you want to delete and click on the picture itself.
It will open up the picture in larger from and in the bottom right corner you will see a delete button.
Click Delete and the picture will be deleted.